Sequential one‐pot multicomponent synthesis of bis‐aminothiazols and evaluation of their antibacterial and antioxidant activities

Abstract

A series of novel bis-thiazoles were synthesized through a one-pot semi-fivecomponent reaction of the prepared α-bisbromo ketones, aldehydes, and thiosemicarbazide in the presence of p-TsOH under reflux condition. Products were obtained in reasonable yields via an efficient, convenient, and simple setup. The inhibitory activity on bacterial growth of the products was studied against Gramnegative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacterial strains (Micrococcus luteus, Staphylococcus aureus) at different concentrations (25, 50, 100, and 200 μg/mL at 600 nm). Most of the products showed inhibitory activity at the concentration of 200 μg/mL. In addition, bis-thiazoles showeed high to moderate antioxidant activity using the diphenylpicrylhydrazyl (DPPH) method. Bis-thiazoles 6i and 6j showed higher antioxidant activity than vitamin C and vitamin E.

Synthesis, antimicrobial, and antioxidant activities of new pyridyl‐ and thiazolyl‐bearing carbohydrazides

“…The remaining protons were observed at their expected aromatic region. The peak at δ 166.79 ppm in 13 Figure 2). The physical data of all synthesized compounds is given in (Table 1).…”

“…The structures of synthesized (E)-N 0 -benzylidene-4-methyl-2-(2-propylpyridin-4-yl)thiazole-5-carbohydrazides (6a-l) were established on the basis of their 1 H and 13 C NMR spectral data and satisfactory high resolution mass spectrometry (HRMS) analysis. The 1 H NMR, 13 C NMR and HRMS spectrums (Figures S 1 -S 24 ) is given in supplementary file. The characteristic peak of amido N-H of compound 6c was observed at δ 12.23 ppm.…”

“…Commercially available chemicals and reagents were used directly without further purification. The synthesized compounds were characterized by 1 H NMR, 13 3.4 | General procedure for the synthesis of substituted (E)-N 0 -benzylidene-4-methyl-2-(2-propylpyridin-4-yl)thiazole-…”

“…In addition, thiamine or vitamin B 1 is one of the most important natural thiazoles. Besides, many commercial drugs contain the thiazole skeleton and have numerous clinical applications, such as the nonsteroidal anti‐inflammatory drugs fentizac and meloxicam, the anticancer drug tiazofurin, the anti‐HIV drug ritonavir, and the immune‐regulating drug fanetizole . The pyridine ring is essential to the structure of many biologically active compounds .…”

“…Besides, many commercial drugs contain the thiazole skeleton and have numerous clinical applications, such as the nonsteroidal antiinflammatory drugs fentizac and meloxicam, the anticancer drug tiazofurin, the anti-HIV drug ritonavir, and the immuneregulating drug fanetizole. [13] The pyridine ring is essential to the structure of many biologically active compounds. [14] Functionalized pyridines are found to be accompanied by many biological activities, such as antioxidant, antimicrobial, [15] β-glucuronidase, [16] and cytotoxicity activities against several human cancer cell lines.…”